The deficit of male-biased genes on the D. melanogaster X chromosome is expression-dependent: a consequence of dosage compensation?

J Mol Evol. 2009 May;68(5):576-83. doi: 10.1007/s00239-009-9235-4. Epub 2009 May 1.


In Drosophila, there is a consistent deficit of male-biased genes on the X chromosome. It has been suggested that male-biased genes may evolve from initially unbiased genes as a result of increased expression levels in males. If transcription rates are limited, a large increase in expression in the testis may be harder to achieve for single-copy X-linked genes than for autosomal genes, because they are already hypertranscribed due to dosage compensation. This hypothesis predicts that the larger the increase in expression required to make a male-biased gene, the lower the chance of this being achievable if it is located on the X chromosome. Consequently, highly expressed male-biased genes should be located on the X chromosome less often than lowly expressed male-biased genes. This pattern is observed in our analysis of publicly available data, where microarray data or EST data are used to detect male-biased genes in D. melanogaster and to measure their expression levels. This is consistent with the idea that limitations in transcription rates may prevent male-biased genes from accumulating on the X chromosome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bias
  • Dosage Compensation, Genetic*
  • Drosophila melanogaster / genetics*
  • Expressed Sequence Tags
  • Female
  • Gene Expression Regulation*
  • Genes, Insect / genetics*
  • Male
  • Oligonucleotide Array Sequence Analysis
  • Phylogeny
  • Sex Characteristics*
  • X Chromosome / genetics*